While it was initially believed that members of his entourage were responsible for the attack, Justin became a prime suspect after he didn’t show up for questioning.

“We’re told Toronto cops wanted to talk to Justin but he didn’t come in for an interview and they got annoyed,” TMZ wrote.

The website also revealed that the dispute was triggered by the volume of the radio.

“Justin was cruising along in Toronto in the back seat of the limo when he wanted the driver to turn up the noise … on the radio. The driver turned it up … but not as much as Justin wanted, and an argument erupted,” a source told the website.

Justin also entered a not guilty plea on Wednesday against charges of driving under the influence, resisting arrest without violence and driving on an expired licence in Miami earlier this month.

Although official toxicology reports have not yet been released, preliminary tests reveal the singer tested positive for both marijuana and Xanax.